Lights/ wiper electrical situation(problem) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**67sss** · 06-24-2003, 08:22 PM

So here's the scoop. The parking lights and tail lights come on when I turn the ign. to the on position, not cranking the engine.
I've tried replacing the light switch, didn't help. Below I have 2 pics, 1 of the plug and 1 diagram. Can someone tell me which plugs on a light switch on a 68 GMC should be hot? The tail/parking lights will go off if I unplug the light switch, which is obvious, but in electrical eleminate all the easy things first.

Wipers. Whats the top prong on the inside for? got blue/yellow wires for the 2 main plug ins but nothing for the one that is by itself?

Thanks in advance for the help.

**67sss** · 06-24-2003, 08:23 PM

2

**67sss** · 06-24-2003, 08:25 PM

wiper motor, the plug above the blue wire is for what?

JimKshortstep4x4 · 06-25-2003, 08:36 AM

The headlight switch should not get power from the ignition switch. There has to be some cross connection in the wiring. I would check the fuse panel and behind the panel first.

On your windshield wipers, the two wires should be for slow and fast speed unless you only have one speed. In a two speed setup, the third terminal is needed, (one power two control wires).

Jim

**67sss** · 06-25-2003, 08:57 PM

thanks for the info.

06-24-2003, 08:22 PM	#1
67sss Registered User Join Date: Nov 2002 Location: Mt. Vernon, WA.. Posts: 2,325	Lights/ wiper electrical situation(problem) So here's the scoop. The parking lights and tail lights come on when I turn the ign. to the on position, not cranking the engine. I've tried replacing the light switch, didn't help. Below I have 2 pics, 1 of the plug and 1 diagram. Can someone tell me which plugs on a light switch on a 68 GMC should be hot? The tail/parking lights will go off if I unplug the light switch, which is obvious, but in electrical eleminate all the easy things first. Wipers. Whats the top prong on the inside for? got blue/yellow wires for the 2 main plug ins but nothing for the one that is by itself? Thanks in advance for the help. Attached Images

06-24-2003, 08:23 PM	#2
67sss Registered User Join Date: Nov 2002 Location: Mt. Vernon, WA.. Posts: 2,325	2 Attached Images

06-24-2003, 08:25 PM	#3
67sss Registered User Join Date: Nov 2002 Location: Mt. Vernon, WA.. Posts: 2,325	wiper motor, the plug above the blue wire is for what? Attached Images

06-25-2003, 08:36 AM	#4
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	The headlight switch should not get power from the ignition switch. There has to be some cross connection in the wiring. I would check the fuse panel and behind the panel first. On your windshield wipers, the two wires should be for slow and fast speed unless you only have one speed. In a two speed setup, the third terminal is needed, (one power two control wires). Jim

06-25-2003, 08:57 PM	#5
67sss Registered User Join Date: Nov 2002 Location: Mt. Vernon, WA.. Posts: 2,325	thanks for the info.



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